1. Field of the Invention
The invention relates to an arrangement for determining on approximation the equivalent circuit diagram of an electrical or electronic element at high frequencies by means of a measuring apparatus, to which the element representing a two-port or one-port element is connected through connection members and which measures the parameters of the stray matrix of the two-port element or the impedance or the reflection factor of the one-port element with the connection members over a preselected frequency range.
2. Description of the Prior Art
Electrical or electronic elements used in the circuits, in which signals having frequencies of more than 10 MHz are processed, have not only the property (for example resistance, inductance, capacitance, amplification etc.) characterizing them, but also parasitic properties. For example, a capacitor has besides its desired capacitance also at least an inductive (parasitic inductance) and an ohmic component (parasitic resistance). A transistor, which has to amplify a signal, for example has a at least a capacitive (parasitic capacitance), an inductive (parasitic inductance) and an ohmic component (parasitic resistance). In order to correctly dimension the circuit, in which the element is used, it is required to know its parasitic properties. For measuring the impedance or the reflection factor of a one-port element, such as, for example, inter alia a resistor and a coil, a measuring apparatus (network analyser) is used, which is known, for example, from GB A 2154752. During measurement, a high-frequency signal is supplied to the one-port element. The reflection factor or the impedance is determined from the reflected signal. Such a measuring apparatus is provided also for measuring the stray matrix of two-port elements, for example, inter alia transistors and band-pass filters. The one-port and two-port elements are connected to one and two standard connections (N connectors), respectively, of the measuring apparatus through connection members. Such connection members falsify the measurement result by parasitic effects originating from them. Such a measuring apparatus does not determine an equivalent circuit diagram either of the one-port or two-port element, but it measures over a preselected frequency range the real and imaginary parts or the amplitude and phase of the impedance or of the reflection factor of a one-port element or the parameters of the stray matrix of a two-port element.